The U.S. military is developing fuel technology to extend the life of its global surveillance satellites. The Defense Advanced Research Projects Agency (DARPA) is working with Proton Energy Systems on the “Water Rocket” program, through which researchers hope to develop a self-regenerating fuel loop that would use water and solar power to create electricity. The new technology is expected to greatly extend the operation time of satellites, to reduce the weight of fuel upon launch and to provide the U.S. military with more options for maneuvering their satellites. “I believe [that moving to self-sustaining satellites] will have far-reaching implications for military, aerospace, homeland defense and commercial applications,” said Jan Walker, a DARPA spokeswoman.